Body fat and body composition explained

I remember that when I first heard about terms such as body fat, lean body mass or lean muscle mass I was a bit confused about the meaning of each of them and I had trouble understanding what more advanced lifters around be were talking about.

Even if you are a complete beginner to dieting and fitness you must know that tracking just your bodyweight doesn’t do the trick. You need to look at your body fat and lean mass and see if you are making progress towards your goals, regardless of what they are. Even though you might not see any changes on the scale but your body fat might be dropping, for example.

Bodyweight is divided in two main categories: body fat and lean body weight.

Body fat

The body fat consists of fat cells and represents all the fat in our bodies – both essential fat and stored fat. Essential fat is used by our bodies in the metabolic processes, and it is something that you cannot live without. For men the essential body fat is in the range of 2-4% of total bodyweight, and 10-12% for women.

Stored fat is basically the excess of fat that our body stores when we eat more calories than we should. The stored fat is used as fuel when we are doing intense physical activates and when we don’t eat enough. That’s when you are burning fat.

Here are some shots on how human body looks like at different body fat levels for men and women.

body-fat-percentage-men body-fat-percentage-women

Body fat is something that any bodybuilder looks at and tries to minimize. Low body fat percentages determine how fit a person looks, gives you muscle definition and separation, and improves aesthetics.

Lean body weight

Lean body weight is everything inside our bodies that it is not fat. It is also called fat free mass. Lead body weight consists of bones, muscles, internal organs, water and blood.

Water weight

Most of the weight in our bodies is just water. To be more specific, for men about 60-62% of the body is water weight and for women about 55-58%. The percentage is slightly lower for women because women hold a little bit more fat than men.

The water in our bodies doesn’t just float around but it is in fact found in our muscles, bones and fat.

Water is responsible for the short time weight variations and that is perfectly normal. Based on what we had to eat and to drink our bodies can hold more or less water, which determine weight variations throughout the day. For example I can see a difference of about 4-5 pounds within the same day. This is perfectly normal.

Bone mass

Total bone mass is around 15% of bodyweight for men and 12% for women. This varies slightly with age, reaching maximum at 30-40 years old.

There is not much you can do to influence the level of bone mass, but exercising and clean eating seems to help maintaining healthy bone density when aging.

Muscle mass

I saved the best for last. Muscle mass is what all lifters and bodybuilders are after. Muscles and fat are the two body composition elements that we can influence a lot by dieting and exercising. Depending on the fitness level, the average muscles mass represents about 38-54% of total bodyweight for men and 28-39% for women. Around 75% of our muscles are made of water.

Both fat and muscle mass are very important components you need to look at in order to determine if you have a healthy body composition or not. Just looking at bodyweight doesn’t tell you much.

Natural lifters can gain a maximum of about 40-50 pounds of muscle in a lifetime and an increased muscle mass percentage means a higher caloric need.

Closing lines

I hope this has been informative and helped you better understand what our bodies are made of. Have you ever got tested for body composition? Do you know how much body fat you have?

Over and out,


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